Thesis--University of Missouri, School of Mines and Metallurgy, 1907. / The entire thesis text is included in file. Typescript. Title from title screen of thesis/dissertation PDF file (viewed December 5, 2008)

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 131-133). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1965. / Typescript. Vita. Description based on print version record. Includes bibliographical references.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1931. / Typescript. With this are bound: A method for the growth of single crystals of low melting point metals in vacuum / by J.H. Dillon. Reprinted from Review of scientific instruments, vol. 1, no. 1 (Jan. 1930), p. 36-38 -- Photoelectric properties of zinc single crystals / by J.H. Dillon. Reprinted from Physical review, vol. 38, no. 3 (1 Aug. 1931) p. 408-415. Includes bibliographical references (leaf [16]).

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (M.S.)--University of Wisconsin--Madison, 1914. / Typescript. eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references (leaf 30).

Thesis (M.S.)--University of Wisconsin--Madison, 1966. / eContent provider-neutral record in process. Description based on print version record. Includes bibliographical references.

Thesis (Ph.D.)--University of Missouri-Columbia, 2004. / Typescript. Vita. Includes bibliographical references (leaves 131-133). Also available on the Internet.

Zinc nitride is currently attracting research interest because of its potential for novel electronic and photonic properties. In this thesis the optical properties of Zn3N2 powders have been investigated by photoluminescence (PL) and diffuse reflectance spectroscopy (DR) measurements. The micro structure and composition of zinc nitride were assessed by scanning electron microscopy (SEM) and powder X-ray diffraction (PXRD). Measurements of PL, PXRD and DR were carried out on zinc nitride powder samples with different oxygen-nitrogen (O/N) ratios. Photoluminescence spectroscopy of the zinc nitride powder samples allows us to find the optical bandgap of the samples. To the best of our knowledge, this is the first report on the low temperature photoluminescence of zinc nitride powder. This showed us how the band gap energy depends on temperature. The diffuse reflectance measurement let us determine a direct bandgap of 1.12eV for Zn3N2 powders and the PL measurements also demonstrated emission at the same photon energy. In this work, the effect of oxidation on the optical properties has been investigated. The surface oxidation of Zn3N2 powders and the oxygen-nitrogen (O/N) ratio were detected through PXRD scans. Our measurement show that the optical bandgap energy shifts to lower energy due to the oxygen incorporation. The reduction of the Zn3N2 bandgap by oxygen incorporation can be explained by a resonant interaction between the extended states of the conduction band of Zn3N2 and localized oxygen states near the conduction band edge. Additionally, the thermal nitriding process was carried out on the oxidized Zn3N2 powders to vary the O/N ratio which increased the bandgap energy. From our result, the optical bandgap of the Zn3N2 powders is estimated to be ~1.2 eV which decreases by small amount of oxygen contamination due to exposure to air. Powder XRD measurements of thermal oxidation of Zn3N2 indicated that the oxidation of these powders is slow at room temperature. / Graduate

The kinetics of the dissolution of zinc in aqueous solutions of ammonia and ethylenediamine under oxygen pressure were investigated at a temperature of 25°C. The variables investigated included free amine concentration, oxygen pressure and stirring rate. Two regions of kinetic control were observed having different dependences on oxygen pressure. At low oxygen pressures, the rate of dissolution of zinc is first order in oxygen pressure, dependent on stirring rate and independent of the free amine concentration. At higher oxygen pressures, an adherent oxide layer is formed on the zinc surface and the rate of dissolution is first order with respect to free amine concentration and independent of oxygen pressure. These results indicate that at low oxygen pressures the rate is controlled by the diffusion of oxygen to the zinc surface; and at high oxygen pressures, the rate of reaction is chemically controlled at the film-solution interface. / Applied Science, Faculty of / Materials Engineering, Department of / Graduate